clear all; close all; clc
a = [1 -0.7]; b = [0.3];
lgn=1000;
l=1:1:lgn;

n=10*randn(1,lgn);
y = filter(b, a, n);
    figure(1);
    plot(l,n,'r',l,y,'b');
    legend('E(t)', 'U(t)')
    xlabel('t, ns')
    ylabel('U_c, E, Volt')
    grid on   